RedexRobB wrote:well ive got rocker cover off, and now i feel stupid. how the hell do you tell? Im looking for a slot on the end of the sprockets, are and i cant really see much. Any other way of telling?
Rob if the sprocket on the end of the cam shaft has two little bolts/screws holding in on then it is a SP camshaft.
You should also see that the holes fr the bolts are slotted so as to allow for valve timing adjustment.................thats why us racers like em.
The standard camshafts have the sprocket pressed on there is NO bolt/screw
superman wrote:i thought the frame numbers started with the letter the bike was hence it said SP at the start of the number or something similar, duno where i got that from thoe.
I've got a SP frame hanging in the workshop.................give me a minute....................
Frame number is ZX400L310293.................nothing to indicate SP or not
No bolts on the sprocket faces and no slotting either by the looks of it. Was quite exciting getting the lot off to find out but a bit of an anti climax
zimm wrote:while on the subject of H/L/SP differences,
cargo, do you know if the SP's have different (ie, stronger) valve springs ?
I coudn't say absolutly for certain that there is a difference in valve springs.................the SP doesn't rev that much higher so at a guess I'd say the valve springs are the same.
I would doubt that you could buy SP valve springs in the UK ? ?
Also I'm fairly sure that RMKD gets his ZXRs reving to 17K on standard valve springs..................and while that causes problems they are not valve related problems.................
funky munky, wasnt sure.. they arent specced as a new part for the old F3 kit and that revs to 15,200rpm, i dont have SP specs here and there's only you and roger that would likely know off-hand.
think roger's bike's running to 16,100 ? 16,300 ? somewhere there.. but he's got magic cams n pixie dust n stuff to allow it to still make power up that high
intechangeability IS one of the likeable things with the zxr's .. all mine are bitsa's to a degree
F3 L models unlike the H's ran to 16,200 rpm. So these are much more likely to have different springs. From what I understand there are at least 2 types of springs in non SP model ZXR's one is painted with a white stripe and one is painted with a green. There may be more, I hope someone can confirm this.
As for the principles behind valve spring ratings ( N/mm) , there are several factors :
1. RPM
2. cam Ramp rates
3. valve train mass ( valve , retainer, collets, bucket , shim, spring )
4. spring preload shimming
the zxr750 sp models came out with alloy retainers in order to lighten the valve mass. I beleive this allowed them to use standard springs with more agressive cams. However if the kit spec CDI and cams were installed. hence higher RPM and higher ramp rates, the kit valve springs were then recomended/required.
So I would think RMKD may be using titanium retainers, as I beleive they did mention something about that. This coupled with careful choice of cam profile could alloy standard valve springs ( maybe ). However as you can see one really needs to look at a given engine (read your engine) and then determine what is required. Simply changing valve springs may not be the only choice.
That said I have reprofiled ZX4 cams with very high lift and duration, I have just increased my RPM limit on the SP box to 16,200rpm as well ( F3 spec M3.) So I am deffinately keen on finding out what springs with the highest N/mm rating are obtainable or standard in certain models. Also interested in titanium retainers.
I think SP models do have lighter buckets and retainers butnot sure.
Hope people can shed some more light on this. Also hope this info has been of help.
